In the condensation reaction for producing polyamide resin or fiber by polymerizing a salt of an organic diamine with an organic diacid, water is formed. Water is also present in the reaction apparatus from the water used to dissolve the initial reactants. In order for the reaction to proceed smoothly, this water must be removed. While the water, in form of steam, is being removed and vented from the evaporation and reaction apparatus, a part of the organic diamine present is inevitably lost through being carried along with the steam. It would be desirable to recover this lost diamine.
Various procedures exist in the art for the removal of organic diamines from aqueous solutions, such as removal by sorption with charcoal or by molecular sorption on an anion exchange resin of a polymeric alkenylaromatic resin crosslinked with a dialkenyl crosslinking agent as described in Sargent, U.S. Pat. No. 3,159,632. However, these procedures do not leave the removed diamine in a form practical for direct reuse, especially reuse in the polymerization process. This invention is directed to a process in which the organic diamine is not only removed, but is also regenerated in a salt form in which it can be directly employed in a variety of uses depending upon the acid used to form the salt.